Field of the Invention
The present invention relates to wireless communication, and more particularly, to a method for transmitting reception confirmation in a wireless communication system and an apparatus using the method.
Related Art
A wireless communication system may use a hybrid automatic repeat request (HARQ). The HARQ is a scheme where a transmitter transmits data and then receivers ACK/NACK (acknowledgement/not-acknowledgement) being reception confirmation information with respect to the data, transmits new data or retransmits the transmitted data according to the ACK/NACK.
3GPP (3rd Generation Partnership Project) LTE (long term evolution)/LTE-A (long term evolution-advanced) may transmit the ACK/NACK through a PUCCH (physical uplink control channel) being an uplink control channel. When the ACK/NACK is transmitted through the PUCCH, a resource (PUCCH resource) configuring the PUCCH may be implicitly or explicitly determined. For example, the PUCCH resource may be determined based on a resource occupied by a PDSCH (physical downlink shared channel) being a target of the ACK/NACK response or a control channel scheduling data (transmission block or code-word). Such a PUCCH resource refers to an implicit PUCCH resource. Meanwhile, a case of explicitly indicating and using one or a plurality of resource according to a higher-layer signal refers to an explicit PUCCH resource.
Meanwhile, the wireless communication system may transmit data by using semi-persistent scheduling (SPS). The semi-persistent scheduling (SPS) is a scheduling method that transmits, when indicating activation/re-activation of the SPS once through a control channel after predesignating subframes that can data through the higher-layer signal, data by a modulation and coding scheme (MCS), a resource, and the like indicated by the control channel by using the predesignated subframes. Therefore, a control channel exists, which corresponds to a data channel in the same subframe as the control channel that indicates the SPS activation/re-activation among data channels transmitted by the SPS, but no control channel corresponding to the data channels by the SPS exists in the corresponding subframe.
In the related art, transmission data by the SPS was used under a predetermined limit. For example, there was a limit that only one SPS is set in downlink subframes which are targets of the ACK/NACK, which are transmitted in one uplink subframe. As a result, only one data channel (SPS data channel) by the SPS is transmitted in the downlink subframes and when the ACK/NACK is transmitted in the uplink subframe, only one SPS data channel is just considered.
However, in a future wireless communication system, the SPS can be used without the limit. Accordingly, an ACK/NACK transmission method premising the limit is modified or a new ACK/NACK transmission is required.